With the development of information, the requirement for the display device is increasing day by day. For satisfying the requirement, there are several flat panel display equipments as LCD, PDP or OLED are developing rapidly. In the flat panel display equipments, the LCD with a lot of advantages as low weight, small size and low energy consumption is replaced the cold cathode display equipment step by step.
The TFT-LCD includes an array substrate, a color film substrate and liquid crystal between the two substrates. To adhere the two substrates together, the sealant is surrounding of the display equipment. The sealant should satisfy the following characteristics:
1) With good adhesion force, then the two substrates could not easy to strip down while on using;
2) With high strength, the display frame could be broken easily;
3) Because the liquid crystal could not contact the oxygen or water, the display frame should insulate from the oxygen and water;
4) The sealant could not mix with the larger impurity particles. If mixing the large impurity particles, the two substrates would be pushed up and then the oxygen and water could easy inflow in, and then the adhesion of the display frame is cut down even bring the two substrates separating and make the TFT-LCD damage, so the sealant should pass thought the filtrating equipment before the finish product achieved.
For ensure the thickness of the side of the liquid display device, some space blocks are provide for filling and mixing with the sealant, e.g. spherical or fibroid space blocks. With the space blocks, the two substrates are adhered to each other to form an uniform thickness frame. The space blocks are uniformly dispersing in the sealant. The bubble should be defoamed before extrusion. If the bubble is existed, the sealant would be easy to break on coating.
On coating, the defoamed sealant which mixing with the space block is inserted in the sealant injector. The sealant injector is made from a non-transparent and metal material and a transparent and plastics material. The upper end of the sealant injector is connecting to the high pressure nitrogen, and the under end is connecting to the spray nozzle. With the pressure of the nitrogen, the sealant could be force out from the spray nozzle. The size of the spray nozzle is about 150˜500 μm that the space block could be go through from the spray nozzle.
During the producing process, with the restriction of the operation and the environment, when on the mixing of the space block, the defoaming or filling of the sealant, the large impurity particles are easy to be inserted into the cavity. The moderate impurity particles would not bring great influence in coating. However, if the size of the impurity particle is more than 10 μm, the display frame would be not uniform and even be scraped.
The sealant should be filtered by the filtrating equipment before molding. But the sealant should not be filtered when on molding. The molding process of the prior art is complex and the produce efficiency is low. In addition, more filtrating equipments should be invested to increase the cost of the manufacture.
Therefore, it is necessary to provide a sealant injector with high production efficiency, simple procedure and the filtering effect well.